Hi,
enlarged spleen can be caused by a number of reasons. My 8 yo ferret
was diagnosed with one when she went in for her tooth extraction. They
found a double abscess in her right jaw upper and bottom tooth. They
removed the lower and I am treating the infection for 23 more days.

Here is a link to a thread I posted on HFF about what an enlarged
spleen can indicate.
<http://holisticferret60.proboards.com/index.cgi?action=display&board=vetting&thread=5912&page=1>

The spleen in her case was enlarged from the infection her body was
trying to fight.

In your girls case Aplastic Anemia might certainly be the cause as
jills are known to die by 1 yo from AA If they are not spayed before
season or mated to bring them out. If that's the case I wonder if the
splenectomy is needed and if her being spayed might fix all her
problems.

[Posted in FML 7352]